1. Field of the Invention
This invention relates to the control of vibrations in structural elements, and in particular to a magnetic feedback control system for controlling or eliminating such vibrations.
2. Prior Art
Many servomechanisms are known which utilize feedback control to damp vibrations in structural members. Typically such systems have been mechanical or electromechanical and have therefore suffered from one or more disadvantages. For example, vibration controllers which depend upon relative motion between moving parts possess inherent mechanical resonances which must be accounted for, either by way of initial design considerations, or by the use of an output signal filtering device of some type. Some prior art devices are sensitive to more than one mode of vibration, or to a limited frequency range of vibration, and thereby provide measurement signals which contain other elements in addition to the vibrations sought to be controlled or eliminated. Other prior art devices involve delicate or expensive sensors and massive dampers or controllers.
Many types of controllers operate directionally, and therefore require that particular axes be carefully aligned for the device to function. Other prior art devices are temperature sensitive or require careful monitoring to provide correction signals related to temperature. Still other devices sense the vibration to be controlled at one location and then attempt to control it at another location therefore requiring careful positioning and/or calibration of the equipment involved.